Use panel.cor function for correlation plots?

[iantaylor-NOAA]

Nathan says "I've found it useful to use the panel.cor function to numerically report the parameter correlations in the upper right triangle of the plot." Seems like an easy change to make for 2016.

[allanhicks]

Nathan says this is the code:

put (absolute) correlations on the upper panels,
with size proportional to the correlations.
panel.cor <- function(x, y, digits = 2, prefix = "", cex.cor, ...)
{
usr <- par("usr"); on.exit(par(usr))
par(usr = c(0, 1, 0, 1))
r <- abs(cor(x, y))
txt <- format(c(r, 0.123456789), digits = digits)[1]
txt <- paste0(prefix, txt)
if(missing(cex.cor)) cex.cor <- 0.8/strwidth(txt)
text(0.5, 0.5, txt, cex = cex.cor * r)
}
pairs(USJudgeRatings, lower.panel = panel.smooth, upper.panel = panel.cor)